Structural health monitoring and diagnostic investigations of the Scrovegni chapel, Italy

The Scrovegni Chapel represents without doubt a masterpiece in the history of painting in Italy and Europe in the 14th century and it is considered the most complete series of frescos executed by Giotto in his mature age. Given the crucial importance of the building from a cultural point of view, in 1995 a systematic research campaign started, including the execution of studies on the structural health state of the Chapel. The final aim is to guarantee optimal preservation conditions on the occasion, and in direct continuation, of the restoration of the Giotto’s frescoes performed in 2001-2002. The investigation plan, based on nondestructive techniques, includes punctual tests, periodically repeated, and continuous monitoring, direct measurements and indirect identifications (back-analysis) of relevant structural parameters. Although the structural layout of the chapel is apparently simple, the protection of the monument is strongly connected to the fact that its historic and artistic value cannot be separated from the structure itself and the effects of strengthening interventions carried out in the last 150 years need to be carefully evaluated. In this framework a structural health monitoring system has been recently installed by the authors. A network of static and dynamic sensors controls the relevant parameters related to the structural safety of the monument and the protection of the artistic content. The paper describes the diagnostic investigations carried out, including ambient vibration tests, crack pattern survey and identification of possible ongoing degradation phenomena. Then the installed monitoring equipment is presented focusing on the algorithms developed and implemented into a processing software to perform the online automatic analysis of static data and the identification of modal parameters. Relevant features extracted from monitoring data are then used as inputs for the application of damage detection algorithms and the numerical calibration of a finite element model of the structure.